As is well known, cytokinins are plant hormones that act in concert with other plant hormones, such as auxins, in regulating many aspects of plant growth and development. Operationally, naturally occurring and synthetic compounds are defined as cytokinins if they promote growth and cell division (hence the name cytokinin, from cytokinesis) of cultured excised plant tissues when such compounds are added to a nutrient medium (containing auxin, vitamins, mineral salts, and sucrose, etc.) upon which the excised tissues are being grown.
Structurally, most cytokinins are derivatives of an adenine-type purine molecule in which the nitrogen at the sixth position is substituted with certain well defined side chain substituents such that the resulting molecules have biological activity similar to that exhibited by the first discovered substance in this series, kinetin. Since the initial discovery of kinetin, a wide variety of cytokinins have been synthesized and studied. As a result of these studies it is now generally known that the type of side chain constituents at N.sub.6 which confer cytokinin activity to adenine are non-polar branched or straight chain aliphatic or aromatic moieties. For example, see Letham, D. S. "Cytokinins" in Phytohormones and Related Compounds - A Comprehensive Treaties, Vol. 1, "The Biochemistry of Phytohormones and Related Compounds", (edited by D. J. Letham, P. B. Goodwin and T. J. V. Higgins), Elsevier/North Holland Medical Press, 1978, Amsterdam.
One of the most important properties of the cytokinins is their ability to regulate development and organ formation in tissue cultures. Practically speaking, this cytokinin effect enables agriculturalists to use these compounds to produce large numbers of genetically engineered plants.
It is known that some ring substituents confer cytokinin activity on adenine if these substituents are linked at the N.sub.6 position on the adenine moiety. However, until the present invention it was not known that adamantane and its derivatives, when linked to adenine at the N.sub.6 position, would also confer cytokinin activity to the adenine molecule.
It is an object of the present invention to provide novel adamantyl purine compounds in which the purine ring is substituted at the 6-position with a moiety incorporating an adamantane ring system.
It is a further object of the present invention to provide novel adamantyl purine compounds in which the 6-position of the purine ring is substituted with a moiety incorporating an adamantane ring system, and the 9-position of the purine ring is substituted with a carbohydrate.
It is a further object of the present invention to provide novel adamantyl purine compounds in which the purine is substituted at the 6-position with an adamantane ring system, either substituted or unsubstituted, and a linker connects the carbon atom in the adamantane ring system with the 6-carbon of the purine ring.
It is a further object of the present invention to provide novel adamantyl purine compounds in which the 6-position of the purine is substituted with an adamantane ring system, either substituted or unsubstituted; the 9-position of the purine is substituted with a carbohydrate; and a linker connects the carbon atom in the adamantane ring system with the 6-carbon of the purine ring.
It is an object of the present invention to provide novel adamantyl adenine compounds in which the adenine ring is substituted at the 6-position with a moiety incorporating an adamantane ring system.
It is a further object of the present invention to provide novel adamantyl adenine compounds in which the 6-position of the adenine ring is substituted with a moiety incorporating an adamantane ring system, and the 9-position of the adenine ring is substituted with a carbohydrate.
It is a further object of the present invention to provide novel adamantyl adenine compounds in which the adenine is substituted at the 6-position with an adamantane ring system, either substituted or unsubstituted, and a linker connects the carbon atom in the adamantane ring system with the 6-carbon of the adenine ring.
It is a further object of the present invention to provide novel adamantyl adenine compounds in which the 6-position of the adenine is substituted with an adamantane ring system, either substituted or unsubstituted; the 9-position of the adenine is substituted with a carbohydrate; and a linker connects the carbon atom in the adamantane ring system with the 6-carbon of the adenine ring.
It is an object of the present invention to provide novel adamantyl purine compounds which exhibit growth regulatory activity in plants.
It is still another object of the present invention to provide novel adamantyl adenine compounds which exhibit enhanced promotion of growth in plant cells.